hdf5_ep

Apparently, + has no special meaning, and neither does \+, in so-called
"obsolete" / POSIX "basic" regular expressions.  Also, not every version of
`sed` out there supports the `-E` option.  So delete the -E flag and use
the regex `[^/][^/]*` instead of `[^/]+`.

Add config/netbsd to the MANIFEST.